Butene-1 polymer composition having a high melt flow rate

ABSTRACT

A butene-1 polymer composition having MFR values of from 400 to 2000 g/10 min, measured according to ISO 1133 at 190° C. with a load of 2.16 kg, made from or containing
     A) a butene-1 homopolymer or a copolymer of butene-1 with a comonomer selected from the group consisting of ethylene and higher alpha-olefins, having a copolymerized comonomer content of up to 5% by mole;   B) a copolymer of butene-1 with a comonomer selected from the group consisting of ethylene and higher alpha-olefins, having a copolymerized comonomer content of from 6% to 20% by mole;
 
wherein the composition having a total copolymerized comonomer content from 4% to 15% by mole, referred to the sum of A) and B), and a content of fraction soluble in xylene at 0° C. of 60% by weight or less, determined on the total weight of A) and B).

FIELD OF THE INVENTION

In general, the present disclosure relates to the field of chemistry.More specifically, the present disclosure relates to polymer chemistry.In particular, the present disclosure relates to a butene-1 polymercomposition.

BACKGROUND OF THE INVENTION

Butene-1 polymers with high melt flow rate have been employed in variouskinds of hot-melt formulations and applications.

SUMMARY OF THE INVENTION

The present disclosure provides a butene-1 polymer composition havingMelt Flow Rate values of from 400 to 2000 g/10 min., alternatively from400 to 1800 g/10 min., alternatively from 400 to 1600 g/10 min.alternatively from 500 to 1600 g/10 min., measured according to ISO 1133at 190° C. with a load of 2.16 kg (hereinafter called “MFR”), made fromor containing

-   -   A) a butene-1 homopolymer or a copolymer of butene-1 with a        comonomer selected from the group consisting of ethylene and        higher alpha-olefins, having a copolymerized comonomer content        (C_(A)) of up to 5% by mole, alternatively up to 4% by mole;    -   B) a copolymer of butene-1 with a comonomer selected from the        group consisting of ethylene and higher alpha-olefins, having a        copolymerized comonomer content (C_(B)) of from 6% to 20% by        mole, alternatively from 8% to 18% by mole;        wherein the composition having a total copolymerized comonomer        content from 4% to 15% by mole, alternatively from 5% to 15% by        mole, referred to the sum of A) and B), and a content of        fraction soluble in xylene at 0° C. of 60% by weight or less,        alternatively of 55% by weight or less, determined on the total        weight of A) and B).        In some embodiments, the composition provided herein is obtained        directly in polymerization, without requiring the use of free        radical generating agents, like peroxides, to increase the MFR        value, thereby avoiding the chemical contamination and        unpleasant odor which results from the introduction of free        radical generating agents.

DETAILED DESCRIPTION OF THE INVENTION

In some embodiments, the amounts of fraction soluble in xylene at 0° C.for the butene-1 polymer composition, expressed as the weight content offraction measured by extraction on the total weight of A) and B), are offrom 35% to 60% by weight, alternatively from 35% to 55% by weight,alternatively from 40% to 60% by weight, alternatively from 40% to 55%by weight.

In some embodiments, A) is a copolymer and the lower limit of comonomercontent is of 1% by mole.

In some embodiments, both A) and B) are copolymers and the differencebetween the percent values of the copolymerized comonomer contents of B)and A) satisfies the following relation:

C _(B))−C _(A))≥5; alternatively

C _(B))−C _(A))≥6.

In some embodiments, the relative amounts of components A) and B) aredetermined depending upon the selected value of total copolymerizedcomonomer content, the comonomer contents of the single components andtheir content of fraction soluble in xylene at 0° C.

In some embodiments, amounts are from 35% to 65% by weight,alternatively from 40% to 60% by weight of A) and from 35% to 65% byweight, alternatively from 40% to 60% by weight of B), based upon thetotal weight of A) and B).

In some embodiments, higher alpha-olefins are present as comonomers, inaddition or in alternative to ethylene, in components A) and B) are thealpha-olefins of formula CH₂═CHR wherein R is methyl or an alkyl radicalcontaining 3 to 8 or 3 to 6 carbon atoms, such as propylene, hexene-1,octene-1.

In some embodiments, ethylene is the comonomer. In some embodiments,ethylene is the comonomer for component B).

The present butene-1 polymer composition has a measurable crystallinity,as demonstrated by the presence, in the Differential ScanningCalorimetry (DSC) pattern, of the melting temperature peaks ofcrystalline butene-1 polymers.

In some embodiments, the present butene-1 polymer composition shows oneor more melting peaks in the second DSC heating scan. In someembodiments, the temperature peak or peaks occur at temperatures equalto or lower than 100° C., alternatively from 75° C. to 100° C., areattributed to the melting point of crystalline form II of the butene-1polymers (TmII) and the area under the peak (or peaks) is taken as theglobal melting enthalpy (DH TmII). In some embodiments, more than onepeak is present and the highest (most intense) peak is taken as TmII.

In some embodiments, global DH TmII values for the present butene-1polymer composition are of 20 J/g or less, alternatively of from 9 to 20J/g, measured with a scanning speed corresponding to 10° C./min.

In some embodiments, the present butene-1 polymer composition shows oneor more melting peaks in a DSC heating scan carried out after aging. Insome embodiments, the melting peaks occur at temperatures equal to orlower than 110° C., alternatively from 30° C. to 110° C. In someembodiments, the temperature peak or peaks are attributed to the meltingpoint crystalline form I of the butene-1 polymers (TmI) and the areaunder the peak (or peaks) is taken as the global melting enthalpy (DHTmI). In some embodiments, more than one peak is present and the highest(most intense) peak is taken as TmI.

In some embodiments, global DH TmI values for the present butene-1polymer composition are of 50 J/g or less, alternatively of from 25 to50 J/g, alternatively from 30 to 50 J/g, measured with a scanning speedcorresponding to 10° C./min.

In some embodiments, the present butene-1 polymer composition has adetectable content of crystalline form III. Crystalline form III isdetectable via the X-ray diffraction method described in the Journal ofPolymer Science Part B: Polymer Letters Volume 1, Issue 11, pages587-591, November 1963, or Macromolecules, Vol. 35, No. 7, 2002.

In some embodiments, X-ray crystallinity values for the present butene-1polymer composition are of from 30% to 60%, alternatively from 35% to55%.

In some embodiments, the MFR values for components A) and B) are broadlyselected, provided that the MFR values of the overall composition areobtained.

The MFR value of a composition made of a blend of the components A) andB) is determined by the following relation:

log MFR(A+B)=wA log MFR(A)+wB log MFR(B)

where MFR (A+B) is the MFR value for the blend of A) and B), MFR (A) andMFR (B) are the MFR values of components A) and B) respectively and wAand wB are the respective weight fractions. For instance, wA and wB areboth 0.5 when the blend is made of 50% by weight of component A) and 50%by weight of component B).

In some embodiments, the MFR values of the single components A) and B)are in the range of from 100 to 2000 g/10 min., alternatively from 200to 1800 g/10 min.

As used herein, the fluidity in the molten state for hot-meltapplications is provided by the “Brookfield viscosity.” In someinstances, Brookfield viscosity is measured according to ASTM D 3236-73.

In some embodiments, the butene-1 polymer composition has Brookfieldviscosity of from 5,000 to 50,000 mPa·sec, at 180° C. and a deformationrate of and 100 s⁻¹, alternatively from 5,000 to 30,000 mPa·sec.

In some embodiments, the Brookfield viscosity is achieved when themolecular weights of the butene-1 polymer composition are low enough,thus when the MFR values are correspondingly high.

In some embodiments, the present butene-1 polymer composition has atleast one of the following further features:

a Mw/Mn value, where Mw is the weight average molar mass and Mn is thenumber average molar mass, both measured by GPC (Gel PermeationChromatography), equal to or lower than 4, alternatively lower than 3,alternatively lower than 2.5, the lower limit being of 1.5;

Mw equal to or greater than 30.000, alternatively from 30.000 to100.000;

an intrinsic viscosity (IV) measured in tetrahydronaphthalene (THN) at135° C. lower than 0.6 dl/g, alternatively from 0.2 dl/g to 0.6 dl/g,alternatively from 0.3 dl/g to 0.6 dl/g;

isotactic pentads (mmmm) measured with ¹³C-NMR operating at 150.91 MHzhigher than 90%; alternatively higher than 93%, alternatively higherthan 95%;

4.1 insertions not detectable using a ¹³C-NMR operating at 150.91 MHz;

a yellowness index lower than 0; alternatively from 0 to −10,alternatively from −1 to −9, alternatively from −1 to −5;

a Shore D value equal to or lower than 50, alternatively equal to orlower than 45, alternatively from 15 to 50, alternatively from 15 to 45;

a tensile stress at break, measured according to ISO 527, of from 3 MPato 25 MPa, alternatively from 4 MPa to 20 MPa;

a tensile elongation at break, measured according to ISO 527, of from400% to 1000%; alternatively from 450% to 700%;

a glass transition temperature of −22° C. or less, alternatively of −23°C. or less, wherein the lower limit is −30° C.

a density of 0.890 g/cm³ or more, alternatively of 0.892 g/cm³ or more;wherein the upper limit is of 0.899 g/cm³.

In some embodiments, the butene-1 polymer components A) and B) areobtained by polymerizing the monomer(s) in the presence of a metallocenecatalyst system obtainable by contacting:

a stereorigid metallocene compound;

an alumoxane or a compound capable of forming an alkyl metallocenecation; and, optionally,

an organo aluminum compound.

In some embodiments, the stereorigid metallocene compound belongs to thefollowing formula (I):

wherein:M is an atom of a transition metal selected from those belonging togroup 4; alternatively M is zirconium;X, equal to or different from each other, is a hydrogen atom, a halogenatom, a R, OR, OR′O, OSO₂CF₃, OCOR, SR, NR₂ or PR₂ group wherein R is alinear or branched, saturated or unsaturated C₁-C₂₀-alkyl,C₃-C₂₀-cycloalkyl, C₆-C₂₀-aryl, C₇-C₂₀-alkylaryl or C₇-C₂₀-arylalkylradical, optionally containing heteroatoms belonging to groups 13-17 ofthe Periodic Table of the Elements; and R′ is a C₁-C₂₀-alkylidene,C₆-C₂₀-arylidene, C₇-C₂₀-alkylarylidene, or C₇-C₂₀-arylalkylideneradical; alternatively X is a hydrogen atom, a halogen atom, a OR′O or Rgroup; alternatively X is chlorine or a methyl radical;R¹, R², R⁵, R⁶, R⁷, R⁸ and R⁹, equal to or different from each other,are hydrogen atoms, or linear or branched, saturated or unsaturatedC₁-C₂₀-alkyl, C₃-C₂₀-cycloalkyl, C₆-C₂₀-aryl, C₇-C₂₀-alkylaryl orC₇-C₂₀-arylalkyl radicals, optionally containing heteroatoms belongingto groups 13-17 of the Periodic Table of the Elements; in someembodiments, R⁵ and R⁶, and/or R⁸ and R⁹ form a saturated orunsaturated, 5 or 6 membered rings, in some embodiments, the ring bearsC₁-C₂₀ alkyl radicals as substituents; with the proviso that at leastone of R⁶ or R⁷ is a linear or branched, saturated or unsaturatedC₁-C₂₀-alkyl radical, optionally containing heteroatoms belonging togroups 13-17 of the Periodic Table of the Elements; alternatively aC₁-C₁₀-alkyl radical;R³ and R⁴, equal to or different from each other, are linear orbranched, saturated or unsaturated C₁-C₂₀-alkyl radicals, optionallycontaining heteroatoms belonging to groups 13-17 of the Periodic Tableof the Elements; alternatively R³ and R⁴ equal to or different from eachother are C₁-C₁₀-alkyl radicals; alternatively R³ is a methyl, or ethylradical; and R⁴ is a methyl, ethyl or isopropyl radical.

In some embodiments, the compounds of formula (I) have formula (Ia):

wherein:M, X, R¹, R², R⁵, R⁶, R⁸ and R⁹ are as described above;R³ is a linear or branched, saturated or unsaturated C₁-C₂₀-alkylradical, optionally containing heteroatoms belonging to groups 13-17 ofthe Periodic Table of the Elements; alternatively R³ is a C₁-C₁₀-alkylradical; alternatively R³ is a methyl, or ethyl radical.

In some embodiments, the metallocene compounds are selected from thegroup consisting of dimethylsilyl{(2,4,7-trimethyl-1-indenyl)-7-(2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene)}zirconium dichloride; dimethylsilanediyl{(1-(2,4,7-trimethylindenyl)-7-(2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene)}Zirconiumdichloride and dimethylsilanediyl{(1-(2,4,7-trimethylindenyl)-7-(2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene)}zirconium dimethyl.

In some embodiments, the alumoxanes are selected from the groupconsisting of methylalumoxane (MAO), tetra-(isobutyl)alumoxane (TIBAO),tetra-(2,4,4-trimethyl-pentyl)alumoxane (TIOAO),tetra-(2,3-dimethylbutyl)alumoxane (TDMBAO) andtetra-(2,3,3-trimethylbutyl)alumoxane (TTMBAO).

In some embodiments, the compounds form an alkylmetallocene cation andare selected from compounds of formula D⁺E⁻, wherein D⁺ is a Brønstedacid, able to donate a proton and to react irreversibly with asubstituent X of the metallocene of formula (I) and E⁻ is a compatibleanion, which is able to stabilize the active catalytic speciesoriginating from the reaction of the two compounds, and which issufficiently labile to be able to be removed by an olefinic monomer. Insome embodiments, the anion E⁻ is made from or contains one or moreboron atoms.

In some embodiments, the organo aluminum compound is selected from thegroup consisting of trimethylaluminum (TMA), triisobutylaluminum (TIBA),tris(2,4,4-trimethyl-pentyl)aluminum (TIOA),tris(2,3-dimethylbutyl)aluminum (TDMBA) andtris(2,3,3-trimethylbutyl)aluminum (TTMBA).

In some embodiments, the catalyst system and polymerization processesemploying the catalyst system are found in Patent Cooperation TreatyPublication Nos. WO2004099269 and WO2009000637.

In some embodiments, the two components A) and B) of the presentbutene-1 polymer composition are prepared separately and then blendedtogether in the molten state by using polymer processing apparatuses. Insome embodiments, the polymer processing apparatuses are mono- or twinscrew extruders.

In some embodiments, the present butene-1 polymer composition isprepared directly in polymerization.

In some embodiments, the polymerization process for producing thecomposition includes at least two sequential stages, carried out in twoor more reactors connected in series, wherein components A) and B) areprepared in separate subsequent stages, operating in each stage, exceptfor the first stage, in the presence of the polymer formed and thecatalyst used in the preceding stage.

In some embodiments, the polymerization process is carried out in liquidphase, optionally in the presence of an inert hydrocarbon solvent. Insome embodiments, the polymerization process is carried out in gasphase, using fluidized bed or mechanically agitated gas phase reactors.

In some embodiments, the catalyst is added in the first reactor only. Insome embodiments, the catalyst is added in more than one reactor.

In some embodiments, the hydrocarbon solvent is aromatic, alternativelytoluene. In some embodiments, the hydrocarbon solvent is aliphatic,alternatively selected from the group consisting of propane, hexane,heptane, isobutane, cyclohexane and 2,2,4-trimethylpentane, isododecane.

In some embodiments, the polymerization process is carried out by usingliquid butene-1 as polymerization medium. The polymerization temperaturecan be from 20° C. to 150° C., alternatively between 50° C. and 90° C.,alternatively from 65° C. to 82° C.

In some embodiments, the concentration of hydrogen in the liquid phaseduring the polymerization reaction (molar ppm H₂/butene-1 monomer) isfrom 1800 ppm to 6000 ppm, alternatively from 1900 ppm to 5500 ppm.

In some embodiments, the amount of comonomer in the liquid phase, when acopolymer is prepared, is from 0.1% to 8% by weight, alternatively from0.2% to 6% by weight, with respect to the total weight of comonomer andbutene-1 monomer present in the polymerization reactor. In someembodiments, the comonomer is ethylene.

In some embodiments, for the preparation of component A) the amount ofcomonomer is from 0.1% to 0.9%, alternatively from 0.2% to 0.8% byweight, while the amount of comonomer is from 1% to 8% by weight,alternatively from 1.5% to 6% by weight for the preparation of componentB).

In some embodiments and in hot-melt adhesive applications, the presentbutene-1 polymer composition is blended with other materials.

In some embodiments, a hot-melt adhesive polyolefin composition is madefrom or contains one or more of the following optional components, inaddition to the present butene-1 polymer composition made from orcontaining the components A) and B):

I) at least one additional polymer;II) at least one resin material different from (I);III) at least one wax or oil; andIV) a nucleating agent.

In some embodiments, the additional polymer is selected from the groupconsisting of amorphous poly-alpha-olefins, thermoplastic polyurethanes,ethyl ene/(meth)acrylate copolymers, ethylene/vinyl acetate copolymersand mixtures thereof. In some embodiments, the resin material differentfrom (I) is selected from the group consisting of aliphatic hydrocarbonresins, terpene/phenolic resins, polyterpenes, rosins, rosin esters andderivatives thereof and mixtures thereof. In some embodiments, the waxor oil is selected from the group consisting of mineral, paraffinic ornaphthenic waxes and oils. In some embodiments, the nucleating agent isselected from the group consisting of isotactic polypropylene,polyethylene, amides, stearamides, and talc.

In some embodiments, the amounts by weight of the optional components,with respect to the total weight of the hot-melt adhesive polyolefincomposition, when present and independently from each other are:

from 0.1% to 25%, alternatively from 1% to 25% by weight of I);

from 10% to 75%, alternatively from 10% to 40% by weight of II);

from 0.1% to 50%, alternatively from 1% to 30% by weight of III);

from 0.01% to 1%, alternatively from 0.1% to 1% by weight of IV).

In some embodiments, the components are added and blended in the moltenstate with the present butene-1 polymer composition by polymerprocessing apparatuses. In some embodiments, the polymer processingapparatuses are mono- or twin screw extruders.

In some embodiments, the hot-melt adhesive compositions are used inpaper and packaging industry, in furniture manufacture and in theproduction of nonwoven articles. In some embodiments, the furnituremanufacture includes edgebands, softforming applications, and panelingin high moisture environments. In some embodiments, the edgebands aresquare edges. In some embodiments, the nonwoven articles includedisposable diapers. In some embodiments, the butene-1 polymercomposition is used as a fluidizer for lubricants.

EXAMPLES

Various embodiments, compositions and methods as provided herein aredisclosed below in the following examples. These examples areillustrative only, and are not intended to limit the scope of theinvention.

The following analytical methods are used to characterize the polymercompositions.

Thermal Properties (Melting Temperatures and Enthalpies)

Determined by Differential Scanning Calorimetry (D.S.C.) on a PerkinElmer DSC-7 instrument, as hereinafter described.

For the determination of TmII (the melting temperature measured in thesecond heating run) a weighed sample (5-10 mg) obtained from thepolymerization was sealed into an aluminum pan and heated at 200° C.with a scanning speed corresponding to 10° C./minute. The sample waskept at 200° C. for 5 minutes to allow a complete melting of thecrystallites. Successively, after cooling to −20° C. with a scanningspeed corresponding to 10° C./minute, the peak temperature was taken asthe crystallization temperature (Tc). After standing for 5 minutes at−20° C., the sample was heated for a second time at 200° C. with ascanning speed corresponding to 10° C./min. In this second heating run,the peak temperature measured was taken as (TmII). If more than one peakwas present, the highest (most intense) peak was taken as TmII. The areaunder the peak (or peaks) was taken as global melting enthalpy (DHTmII).

The melting enthalpy and the melting temperature were also measuredafter aging (without cancelling the thermal history) as follows by usingDifferential Scanning Calorimetry (D.S.C.) on a Perkin Elmer DSC-7instrument. A weighed sample (5-10 mg) obtained from the polymerizationwas sealed into an aluminum pan and heated at 200° C. with a scanningspeed corresponding to 10° C./minute. The sample was kept at 200° C. for5 minutes to allow a complete melting of the crystallites. The samplewas then stored for 10 days at room temperature. After 10 days thesample was subjected to DSC, cooled to −20° C., and then the sample washeated at 200° C. with a scanning speed corresponding to 10° C./min. Inthis heating run, the peak temperature was taken as the meltingtemperature (TmI). If more than one peak was present, the highest (mostintense) peak was taken as TmI. The area under the peak (or peaks) wastaken as global melting enthalpy after 10 days (DH TmI).

MFR

Determined according to norm ISO 1133 with a load of 2.16 kg at 190° C.(standard die).

Intrinsic Viscosity

Determined according to norm ASTM D 2857 in tetrahydronaphthalene at135° C.

Brookfield Viscosity

Measured at 180° C. and a deformation rate of 100 s⁻¹, using a RheolabQCinstrument, which is a rotational rheometer, consisting of ahigh-precision encoder and a dynamic EC motor. During the test, thesample was subjected at a deformation rate sweep from 1 s⁻¹ to 1000 s⁻¹.The torque was measured for each deformation rate and the correspondingviscosity was calculated by the instrument software.

Density

The density of samples was measured according to ISO 1183-1 (ISO 1183-1method A “Methods for determining the density of non-cellularplastics—Part 1: Immersion method, liquid pyknometer method andtitration method”; Method A: Immersion method, for solid plastics(except for powders) in void-free form). Test specimens were taken fromcompression-molded plaques conditioned for 10 days before carrying outthe density measure.

Comonomer Contents

Comonomer contents were determined via FT-IR.

The spectrum of a pressed film of the polymer was recorded in absorbancevs. wavenumbers (cm⁻¹). The following measurements were used tocalculate the ethylene content:

-   a) area (A_(t)) of the combination absorption bands between 4482 and    3950 cm⁻¹ which is used for spectrometric normalization of film    thickness.-   b) factor of subtraction (FCR_(C2)) of the digital subtraction    between the spectrum of the polymer sample and the absorption band    due to the sequences BEE and BEB (B: 1, butene units, E: ethylene    units) of the methylenic groups (CH₂ rocking vibration).-   c) Area (A_(C2,block)) of the residual band after subtraction of the    C₂PB spectrum. It comes from the sequences EEE of the methylenic    groups (CH₂ rocking vibration).

Apparatus

A Fourier Transform Infrared spectrometer (FTIR) was used.

A hydraulic press with platens heatable to 200° C. (Carver orequivalent) was used.

Method

Calibration of (BEB+BEE) Sequences

A calibration straight line was obtained by plotting % (BEB+BEE)wt vs.FCR_(C2)/A_(t). The slope G_(r) and the intercept I_(r) were calculatedfrom a linear regression.

Calibration of EEE Sequences

A calibration straight line was obtained by plotting % (EEE)wt vs.A_(C2,block)/A_(t). The slope G_(H) and the intercept I_(H) werecalculated from a linear regression.

Sample Preparation

Using a hydraulic press, a thick sheet was obtained by pressing about1.5 g of sample between two aluminum foils. If homogeneity was inquestion, a minimum of two pressing operations were performed. A smallportion was cut from the sheet to mold a film. The film thickness rangedbetween 0.1-0.3 mm.

The pressing temperature was 140±10° C.

The IR spectrum of the sample film was collected as soon as the samplewas molded.

Procedure

The instrument data acquisition parameters were as follows:

Purge time: 30 seconds minimum.Collect time: 3 minutes minimum.

Apodization: Happ-Genzel.

Resolution: 2 cm⁻¹.Collect the IR spectrum of the sample vs. an air background.

Calculation

Calculate the concentration by weight of the BEE+BEB sequences ofethylene units:

${\% \left( {{BEE} + {BEB}} \right){wt}} = {{G_{r} \cdot \frac{{FCR}_{C\; 2}}{A_{t}}} + I_{r}}$

Calculate the residual area (AC2,block) after the subtraction describedabove, using a baseline between the shoulders of the residual band.

Calculate the concentration by weight of the EEE sequences of ethyleneunits:

${\% ({EEE}){wt}} = {{G_{H} \cdot \frac{A_{{C\; 2},{block}}}{A_{t}}} + I_{H}}$

Calculate the total amount of ethylene percent by weight:

% C2wt=[%(BEE+BEB)wt+%(EEE)wt]

NMR Analysis of Chain Structure

¹³C NMR spectra were acquired on a Bruker AV-600 spectrometer equippedwith cryo-probe, operating at 150.91 MHz in the Fourier transform modeat 120° C.

The peak of the T_(βδ) carbon (nomenclature according to C. J. Carman,R. A. Harrington and C. E. Wilkes, Macromolecules, 10, 3, 536 (1977))was used as an internal reference at 37.24 ppm. The samples weredissolved in 1,1,2,2-tetrachloroethane-d2 at 120° C. with an 8% wt/vconcentration. Each spectrum was acquired with a 900 pulse, 15 secondsof delay between pulses and CPD to remove ¹H-¹³C coupling. About 512transients were stored in 32K data points using a spectral window of9000 Hz.

The assignments of the spectra, the evaluation of triad distribution andthe composition were made according to Kakugo [M. Kakugo, Y. Naito, K.Mizunuma and T. Miyatake, Macromolecules, 16, 4, 1160 (1982)] andRandall [J. C. Randall, Macromol. Chem Phys., C30, 211 (1989)] using thefollowing:

BBB=100(T _(ββ))/S=I5

BBE=100T _(βδ) /S=I4

EBE=100P _(δδ) /S=I14

BEB=100S _(ββ) /S=I13

BEE=100Sαδ/S=I7

EEE=100(0.25S _(γδ)+0.5S _(δδ))/S=0.25I9+0.5I10

Area Chemical Shift Assignments Sequence 1 40.40-40.14 Sαα BBBB 2 39.64Tδδ EBE 39-76-39.52 Sαα BBBE 3 39.09 Sαα EBBE 4 37.27 Tβδ BBE 535.20-34.88 Tββ BBB 6 34.88-34.49 Sαγ BBEB + BEBE 7 34.49-34.00 SαδEBEE + BBEE 8 30.91 Sγγ BEEB 9 30.42 Sγδ BEEE 10 29.90 Sδδ EEE 1127.73-26.84 Sβδ + 2B₂ BBB + BBE EBEE + BBEE 12 26.70 2B₂ EBE 1324.54-24.24 Sββ BEB 14 11.22 Pδδ EBE 15 11.05 Pβδ BBE 16 10.81 Pββ BBB

To a first approximation, the mmmm was calculated using 2B2 carbons asfollows:

Area Chemical shift assignments B1  28.2-27.45 mmmm B2 27.45-26.30 mmmm= B₁*100/(B₁ + B₂ − 2*A₄ − A₇ − A₁₄)

Mw/Mn Determination by GPC

Measured by way of Gel Permeation Chromatography (GPC) in1,2,4-trichlorobenzene (TCB). Molecular weight parameters (Mn, Mw, Mz)and molecular weight distributions Mw/Mn for the samples were measuredby using a GPC-IR apparatus by PolymerChar, which was equipped with acolumn set of four PLgel Olexis mixed-bed (Polymer Laboratories) and anIR5 infrared detector (PolymerChar). The dimensions of the columns were300×7.5 mm and their particle size was 13 μm. The mobile phase flow ratewas kept at 1.0 mL/min. The measurements were carried out at 150° C.Solution concentrations were 2.0 mg/mL (at 150° C.) and 0.3 g/L of2,6-diterbuthyl-p-chresole were added to prevent degradation. For GPCcalculation, a universal calibration curve was obtained using 12polystyrene (PS) reference samples supplied by PolymerChar (peakmolecular weights ranging from 266 to 1220000). A third-order polynomialfit was used to interpolate the experimental data and obtain therelevant calibration curve. Data acquisition and processing was done byusing Empower 3 (Waters). The Mark-Houwink relationship was used todetermine the molecular weight distribution and the relevant averagemolecular weights: the K values were K_(PS)=1.21×10⁻⁴ dL/g andK_(PB)=1.78×10⁻⁴ dL/g for PS and polybutene (PB) respectively, while theMark-Houwink exponents α=0.706 for PS and α=0.725 for PB were used.

For butene/ethylene copolymers, it was assumed for each sample that thecomposition was constant in the whole range of molecular weight and theK value of the Mark-Houwink relationship was calculated using a linearcombination as reported below:

K _(EB) =x _(E) K _(PE) +x _(B) K _(PB)

where K_(EB) is the constant of the copolymer, K_(PE) (4.06×10⁻⁴, dL/g)and K_(PB) (1.78×10⁻⁴ dL/g) are the constants of polyethylene (PE) andPB, x_(E) and x_(B) are the ethylene and the butene weight relativeamount with x_(E)+x_(B)=1. The Mark-Houwink exponents α=0.725 was usedfor the butene/ethylene copolymers independently on the composition. Endprocessing data treatment was fixed for the samples to include fractionsup at 1000 in terms of molecular weight equivalent. Fractions below 1000were investigated via GC.

Fractions Soluble and Insoluble in Xylene at 0° C. (XS-0° C.)

2.5 g of polymer composition and 250 cm³ of o-xylene were introducedinto a glass flask equipped with a refrigerator and a magnetic stirrer.The temperature was raised in 30 minutes up to the boiling point of thesolvent. The obtained clear solution was then kept under reflux andstirring for further 30 minutes. The closed flask was then cooled to100° C. in air for 10 to 15 minutes under stirring and then kept for 30minutes in thermostatic water bath at 0° C. for 60 minutes. The formedsolid was filtered on quick filtering paper at 0° C. 100 cm³ of thefiltered liquid was poured in a pre-weighed aluminum container which washeated on a heating plate under nitrogen flow, to remove the solvent byevaporation. The percent by weight of polymer soluble (Xylene Solublesat 0° C.=XS 0° C.) was calculated from the average weight of theresidues. The insoluble fraction in o-xylene at 0° C. (xylene Insolublesat 0° C.=XI %0° C.) was:

XI%0° C.=100−XS%0° C.

Determination of X-Ray Crystallinity

The X-ray crystallinity was measured with an X-ray Diffraction PowderDiffractometer (XDPD) that uses the Cu-Kα1 radiation with fixed slitsand able to collect spectra between diffraction angle 2Θ=5° and 2Θ=35°with step of 0.1° every 6 seconds.

The samples were diskettes of about 1.5-2.5 mm of thickness and 2.5-4.0cm of diameter made by compression molding. The diskettes were aged atroom temperature (23° C.) for 96 hours.After this preparation the specimen was inserted in the XDPD sampleholder. The XRPD instrument was set to collect the XRPD spectrum of thesample from diffraction angle 2Θ=5° to 2Θ=35° with steps of 0.1° byusing counting time of 6 seconds, and at the end the final spectrum wascollected.Ta was defined as the total area between the spectrum profile and thebaseline expressed in counts/sec-20. Aa was defined as the totalamorphous area expressed in counts/sec·2Θ. Ca was defined as the totalcrystalline area expressed in counts/sec-2Θ.The spectrum or diffraction pattern was analyzed in the following steps:1) define a linear baseline for the whole spectrum and calculate thetotal area (Ta) between the spectrum profile and the baseline;2) define an amorphous profile, along the whole spectrum, that separate,the amorphous regions from the crystalline ones according to the twophase model;3) calculate the amorphous area (Aa) as the area between the amorphousprofile and the baseline;4) calculate the crystalline area (Ca) as the area between the spectrumprofile and the amorphous profile as Ca=Ta−Aa; and5) Calculate the degree of crystallinity (% Cr) of the sample using theformula:

%Cr=100×Ca/Ta

Shore D

According to norm ISO 868, measured 10 days after molding.

Tensile Stress and Elongation at Break

According to norm ISO 527 on compression molded plaques, measured 10days after molding.

Glass Transition Temperature Via DMTA (Dynamic Mechanical ThermalAnalysis)

Molded specimens of 76 mm by 13 mm by 1 mm were fixed to a DMTA machinefor tensile stress. The frequency of the tension was fixed at 1 Hz. TheDMTA translated the elastic response of the specimen starting from −100°C. to 130° C. The elastic response was plotted versus temperature. Theelastic modulus for a viscoelastic material was defined as E=E′+iE″. TheDMTA split the two components E′ and E″ by their resonance and plottedE′ vs temperature and E′/E″=tan (δ) vs temperature.The glass transition temperature Tg was assumed to be the temperature atthe maximum of the curve E′/E″=tan (δ) vs temperature.

Yellowness Index

Determined accordingly to ASTM D1925.

Example 1 and Comparative Example 1 Preparation of the MetalloceneCatalyst (A-1)

Dimethylsilyl{(2,4,7-trimethyl-1-indenyl)-7-(2,5-dimethyl-cyclopenta[1,2-b:4,3-b′]-dithiophene)}zirconium dichloride (A-1) was prepared according to Example 32 ofPatent Cooperation Treaty Publication No. WO0147939.

Preparation of the Catalytic Solution

Under nitrogen atmosphere, 8.1 L of a solution of 4.5% wt/v of TIBA inisododecane (1.84 mol of TIBA) and 760 mL of a solution 30% wt/wt of MAOin toluene (3.65 moles of MAO) were loaded in a 20 L jacketed glassreactor equipped with an anchor stirrer and allowed to react at roomtemperature for about 1 hour under stirring.

After this time, the metallocene A-1 (1.6 g, 2.75 mmol) was added anddissolved under stirring for about 30 minutes.

The final solution was discharged from the reactor into a cylinderthrough a filter to remove solid residues (if any).

The composition of the solution was as follows:

Metallocene Al Zr Al/Zr Conc. g/L % w mol ratio mg/L 16.7 0.028 1996 181

Polymerization

The polymerization was carried out continuously in a pilot plantincluding two stirred reactors connected in series in which liquidbutene-1 constituted the liquid medium.

The catalytic solution was fed in the first reactor only.

Comparative Example 1 was carried out by using one reactor only.

The polymerization conditions are reported in Table 1.

TABLE 1 Ex. 1 Comp. 1 Operative conditions (first reactor) Temperature(° C.) 75 75 H₂ in liquid phase (ppm mol) 2329 2600 C₂H₄ in liquid phase(weight %) 0.33 1.24 Mileage (kg/gMe) 2708 2500 Split (weight %) 50 —C₂H₄ content of A) (weight %) 1 — C₂H₄ content of A) (mole %) 2Operative conditions (second reactor) Temperature (° C.) 75 — H₂ inliquid phase (ppm mol) 2290 — C₂H₄ in liquid phase (weight %) 2.8 —Split (weight %) 50 — C₂H₄ content of B) (weight %) 6.8 — C₂H₄ contentof B) (mole %) 12.7 — Total mileage 1722 2500 Total C₂H₄ content (weight%) 3.9 3.5 Total C₂H₄ content (mole %) 7.5 6.8 Note: kg/gMe = kilogramsof polymer per gram of metallocene catalyst (A-1); Split = amount ofpolymer produced in the concerned reactor.

In Table 2 the properties of the final products are specified.

TABLE 2 Ex. 1 Comp. 1 MFR 190° 2.16 Kg - ISO 1133 g/10 min 630 650Intrinsic Viscosity (THN) dl/g 0.49 0.44 C₂H₄ IR % 3.9 3.9 TmII ° C.82.5 71 DH TmII J/g 13.5 1.9 TmI ° C. 94 71.5 DH TmI J/g 37 30 Tc ° C.N.D. N.D. X - Ray crystallinity % 46 33 13C-NMR (mmmm) % 97.1 95.2Xylene Soluble at 0° C. % 48 99.7 Mw g/mol 66450 70174 Mn g/mol 2990034490 Brookfield viscosity at 180° C. mPa · sec 16000 16000 Densityg/cm³ 0.8981 0.8902 Strength at Break MPa 14 13 Elongation at Break %480 400 Hardness Shore D D 40.8 36.8 Glass transition temperature ° C.−25.9 −21 Yellowness Index NR −3 −2.6 Note: N.D. = Not Detectable

What is claimed is:
 1. A butene-1 polymer composition having MFR valuesof from 400 to 2000 g/10 min., measured according to ISO 1133 at 190° C.with a load of 2.16 kg, comprising: A) a butene-1 homopolymer or acopolymer of butene-1 with a comonomer selected from the groupconsisting of ethylene and higher alpha-olefins, having a copolymerizedcomonomer content (C_(A)) of up to 5% by mole; and B) a copolymer ofbutene-1 with a comonomer selected from the group consisting of ethyleneand higher alpha-olefins, having a copolymerized comonomer content(C_(B)) of from 6% to 20% by mole; wherein the composition having atotal copolymerized comonomer content from 4% to 15% by mole referred tothe sum of A) and B), and a content of fraction soluble in xylene at 0°C. of 60% by weight or less determined on the total weight of A) and B).2. The butene-1 polymer composition of claim 1, comprising: from 35% to65% by weight of A) and from 35% to 65% by weight of B), referred to thetotal weight of A) and B).
 3. The butene-1 polymer composition of claim1, having DH TmII values of from 9 to 20 J/g, measured with a scanningspeed corresponding to 10° C./min.
 4. The butene-1 polymer compositionof claim 1, having a Brookfield viscosity of from 5,000 to 50,000mPa·sec, measured at 180° C. and a deformation rate of 100 s⁻¹.
 5. Thebutene-1 polymer composition of claim 1, having a Mw/Mn value, where Mwis the weight average molar mass and Mn is the number average molarmass, both measured by GPC, equal to or lower than
 4. 6. The butene-1polymer composition of claim 1, having a Mw value equal to or greaterthan 30.000.
 7. The butene-1 polymer composition of claim 1, having aglass transition temperature of −22° C. or less.
 8. The butene-1 polymercomposition of claim 1, having a yellowness index lower than
 0. 9. Aprocess for preparing the butene-1 polymer composition of claim 1,comprising: at least two sequential stages, carried out in two or morereactors connected in series, wherein components A) and B) are preparedin separate subsequent stages, operating in each stage, except the firststage, in the presence of the polymer formed and the catalyst used inthe preceding stage.
 10. The process of claim 9, carried out in thepresence of a metallocene catalyst obtainable by contacting: astereorigid metallocene compound; an alumoxane or a compound capable offorming an alkyl metallocene cation; and, optionally, an organo aluminumcompound.
 11. A hot-melt adhesive composition comprising: the butene-1polymer composition of claim 1.